Ø1/2" Post Holders


Ø1/2" Post Holders

  • Precision Wide, Square Relief Provides a Highly Stable Two-Line Contact with the Mating Post
  • Each Post Holder Includes One Spring-Loaded Hex-Locking Thumbscrew


  • Precision-Machined Square Relief Cut Provides Stable Two-Line Contact with Ø1/2" Posts
  • Spring-Loaded, Hex-Locking, Aluminum Thumbscrew Firmly Holds Post
  • Standard Versions: Bottom-Located 1/4"-20 (M6) Tapped Hole Ideal for Mounting to Our Tables
  • Pedestal Versions: Bottom-Located "Pedestal Style" Base with Magnets for Stability Prior to Lockdown (Compatible with CF Series Clamping Forks)

Thorlabs' PH series of posts are the ideal solution for mounting optical components when a specific height for a setup has not been determined. These posts come in two styles: a standard post, which can be mounted to any one of our Mounting Bases via a 1/4"-20 (M6) cap screw, and pedestal posts with a base that works in conjunction with the CF series of clamping forks featured below. Thorlabs' pedestal post holders incorporate high strength magnets in the base to provide holding force while performing rough alignments.

All imperial post holders come with TS25H 3/16" hex spring-loaded thumbscrews, while the metric post holders come with TS6H/M 5 mm hex spring-loaded thumbscrews.

In addition to the post holder options presented here, Thorlabs also offers the UPH series of post holders, which have an attached swivel base.


Ø1/2" Post Holders

  * Aluminum, Spring-Loaded, Hex-Locking Thumbscrews (3/16" or 5 mm) for Positioning Ease
  *  Extra Wide Relief Cut Provides a Two-Line Stable Contact for Post
  *  1/4"-20 (M6) Tapped Hole on Bottom

Thorlabs’ post holders are designed with a wide, square relief cut that provides two lines of contact for highly stable post mounting. A spring-loaded plunger within the aluminum thumbscrew holds a steel post firmly within the post holder prior to final tightening. This design allows one-handed positioning of post-mounted devices. The post holder is compatible with our entire line of table bases and base adapters (see below). Thorlabs' imperial and metric post holders are equipped with our 3/16" (TS25H) and 5 mm (TS6H/M) spring-loaded hex-locking thumbscrews, respectively (available below).


Ø1/2" Pedestal Post Holders

 * Aluminum, Spring-Loaded, Hex-Locking Thumbscrews (3/16" or 5 mm) for Positioning Ease
 * Three High Strength Magnets in Base Provide Holding Force Prior to Fastening
 * Extra Wide Relief Cut Provides a Two-Line Stable Contact for Post
 * Post can Pass Through Base Allowing Minimal Beam Height

These pedestal-style post holders combine the versatility of our standard post holders with the small footprint of the pedestal and fork design. The post holder can be locked down to an optical breadboard using either a CF125 or CF175 clamping fork (see below). When combined with a clamping fork, the fork can be swiveled 360° to pick up the most convenient mounting hole. To further enhance this mounting system, magnets have been added to allow temporary positioning of the post holder prior to lockdown. The through hole design allows the maximum range of post height adjustment. Thorlabs' imperial and metric Pedestal-Style Post Holders are equipped with our 3/16" (TS25H) and 5 mm (TS6H/M) spring-loaded-hex locking thumbscrews, respectively (available below).


Base Adapters and Clamping Forks


  • Combine BE1 Adapter Converts Standard PH Series Post Holder into Pedestal-Style Mount
  • Clamping Fork Secures Pedestal-Style Mount to a Breadboard or Table
  • Two Sizes: CF125 (1.25" Counterbored Slot) and CF175 (1.75" Counterbored Slot)
  • Swivel Fork ±360° to Pick Up Most Convenient Mounting Hole

Pedestal Base Adapter
The BE1 fastens to the base of our standard PH Series Post Holders (as shown to the right) and RS Series Ø1" Pillar Posts to convert them into Pedestal-Style mounts. This combination provides a high degree of mounting flexibility. Note: Together, the BE1 Base Adapter and PH Series Post Holder provide nearly the same design to that of the PHxE Series Pedestal-Style Post Holder without the magnets in the base and through hole design.

Clamping Forks
Our solid stainless steel clamping forks are designed to provide exceptional clamping force when used with our pedestal-style posts and post holders. Use a 1/4"-20 (M6) cap screw and washer combination to lock down the base/fork combination. Please note that significant overtightening of clamping forks can deform the surface of an optical table, which can cause misalignment of components.


Swivel Base Adapter


  • Convert Your Existing Post Holders into Universal Post Holder Style Mounts
  • 360 Degree Swiveling Base Fastens to Existing Ø1/2" Post Holders via a 1/4"-20 (M6) Cap Screw
  • Magnets in Base Hold Position of Components on Breadboard During Initial Setup

Our 360° swivel base adapter fits all standard Ø1/2" post holders with 1/4"-20 (M6) mounting holes and minimizes the amount of time it takes to assemble an optical system. In addition, the swivel design is ideal for applications that require a large number of components to be packed into a small area. When our Ø1/2" post holders are used with the UPHA adapter, the combination is nearly that of our very popular Universal Post Holders. This  anodized aluminum UPHA adapter has the benefit of compatibility with any of our existing Ø1/2" post holders but does not offer the same height flexibility of the UPH series post holders, which allow the post to be lowered all the way to the table.


1/4"-20 and M6 x 1.0 Thumbscrews for Post Holders


Spring-Loaded Hex Locking Thumbscrews (TS25H and TS6H/M): These anodized aluminum thumbscrews have spring-loaded, completely retractable Delrin™ tips that provide sufficient force on a post to hold it in place as final positional adjustments are being made. They can then be locked into place using a 3/16" or 5 mm balldriver to prevent any further movement of the post. The hex size is also engraved on the face of the thumbscrew, thereby enabling easy identification in the lab.

The TS25H is 1/4"-20 threaded for compatibility with our imperial Ø1/2" Post Holders, while the TS6H/M is M6 threaded for compatibility with our metric post holders. Please note that we do not recommend using an L wrench to tighten the thumbscrew in place, as this may break off the screw head. Recommended max torque: 28 in·lbs.


Our Mission is to accelerate the advancement of optical technology for precision measurements and their applications from the table tops of research laboratories to standard use in communication and high technology industries. Our aim is to serve our customers. Our hope is to create a place for highly skilled people in an open environment

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